U.S. patent application number 14/546390 was filed with the patent office on 2015-05-21 for hydraulic control circuit for drive line.
The applicant listed for this patent is Toyota Jidosha Kabushiki Kaisha. Invention is credited to Seiji Kuwahara, Koki Minamikawa, Naoki Nakanishi, Toshio Sugimura, Takahiko Tsutsumi, Masato Yoshikawa.
Application Number | 20150136253 14/546390 |
Document ID | / |
Family ID | 53172072 |
Filed Date | 2015-05-21 |
United States Patent
Application |
20150136253 |
Kind Code |
A1 |
Kuwahara; Seiji ; et
al. |
May 21, 2015 |
HYDRAULIC CONTROL CIRCUIT FOR DRIVE LINE
Abstract
A hydraulic control circuit for a drive line includes first and
second switching valves and first and second solenoid valves. Each
switching valve is alternatively switched by a switching hydraulic
pressure to connect any two of three ports. The first port of the
first switching valve is connected to a hydraulic actuator. The
first port of the second switching valve is connected to the second
port of the first switching valve. The first solenoid valve
supplies the switching hydraulic pressure to the switching valves.
The second solenoid valve regulates a control hydraulic pressure
supplied to the hydraulic actuator. Any one of three oil paths is
communicated with the hydraulic actuator by supplying the control
hydraulic pressure via the third port of the first switching valve
or the second or third port of the second switching valve and
supplying the switching hydraulic pressure to at least one
switching valve.
Inventors: |
Kuwahara; Seiji; (Toyota-shi
Aichi-Ken, JP) ; Sugimura; Toshio; (Nagoya-shi
Aichi-ken, JP) ; Tsutsumi; Takahiko; (Nisshin-shi
Aichi-ken, JP) ; Yoshikawa; Masato; (Toyota-shi
Aichi-ken, JP) ; Minamikawa; Koki; (Nagoya-shi
Aichi-ken, JP) ; Nakanishi; Naoki; (Toyota-shi
Aichi-ken, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Toyota Jidosha Kabushiki Kaisha |
Toyota-shi Aichi-ken |
|
JP |
|
|
Family ID: |
53172072 |
Appl. No.: |
14/546390 |
Filed: |
November 18, 2014 |
Current U.S.
Class: |
137/596 |
Current CPC
Class: |
F16D 2048/0266 20130101;
Y10T 137/87169 20150401; F16D 2048/0281 20130101; F16D 25/14
20130101; F16D 2048/0221 20130101; Y02T 10/62 20130101; F16D 48/02
20130101; F16D 2500/3024 20130101; F16D 2048/0209 20130101 |
Class at
Publication: |
137/596 |
International
Class: |
F16D 48/02 20060101
F16D048/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 19, 2013 |
JP |
2013-239373 |
Oct 24, 2014 |
JP |
2014-217830 |
Claims
1. A hydraulic control circuit for a drive line, the hydraulic
control circuit comprising: a first switching valve configured to
be alternatively switched by a switching hydraulic pressure so as
to connect any two of a first port, a second port and a third port,
the first port of the first switching valve being connected to a
hydraulic actuator; a second switching valve configured to be
alternatively switched by the switching hydraulic pressure so as to
connect any two of a first port, a second port and a third port,
the first port of the second switching valve being connected to the
second port of the first switching valve; a first solenoid valve
provided in common to the first switching valve and the second
switching valve, the first solenoid valve being configured to
supply the switching hydraulic pressure to the first switching
valve and the second switching valve; and a second solenoid valve
configured to regulate a hydraulic pressure as a control hydraulic
pressure, the hydraulic pressure being supplied to the hydraulic
actuator, any one of three oil paths being communicated with the
hydraulic actuator by supplying the control hydraulic pressure from
the second solenoid valve to the hydraulic actuator via any one of
the third port of the first switching valve, the second port of the
second switching valve and the third port of the second switching
valve and supplying the switching hydraulic pressure from the first
solenoid valve to at least one of the first switching valve or the
second switching valve.
2. The hydraulic control circuit according to claim 1, wherein the
three oil paths include a first oil path, a second oil path and a
third oil path, when a predetermined switching hydraulic pressure
is not output and the control hydraulic pressure does not satisfy a
predetermined condition, the first oil path is set by communicating
the first port of the first switching valve and the second port of
the first switching valve, the first port of the second switching
valve and the second port of the second switching valve, and the
hydraulic actuator with one another, when the predetermined
switching hydraulic pressure is output and the control hydraulic
pressure does not satisfy the predetermined condition, the second
oil path is set by communicating the first port of the first
switching valve and the third port of the first switching valve
with the hydraulic actuator, and when the predetermined switching
hydraulic pressure is output and the control hydraulic pressure
satisfies the predetermined condition, the third oil path is set by
communicating the first port of the first switching valve and the
second port of the first switching valve, the first port of the
second switching valve and the third port of the second switching
valve, and the hydraulic actuator with one another.
3. The hydraulic control circuit according to claim 2, wherein the
predetermined condition is a condition that the control hydraulic
pressure is higher than or equal to a predetermined value.
4. The hydraulic control circuit according to claim 2, wherein the
predetermined condition is a condition that the control hydraulic
pressure is lower than a predetermined value.
5. The hydraulic control circuit according to claim 1, wherein the
three oil paths include a first oil path, a second oil path and a
third oil path, when a predetermined switching hydraulic pressure
is output and the control hydraulic pressure does not satisfy a
predetermined condition, the first oil path is set by communicating
the first port of the first switching valve and the second port of
the first switching valve, the first port of the second switching
valve and the second port of the second switching valve, and the
hydraulic actuator with one another, when the predetermined
switching hydraulic pressure is not output and the control
hydraulic pressure does not satisfy the predetermined condition,
the second oil path is set by communicating the first port of the
first switching valve and the third port of the first switching
valve with the hydraulic actuator, and when the predetermined
switching hydraulic pressure is output and the control hydraulic
pressure satisfies the predetermined condition, the third oil path
is set by communicating the first port of the first switching valve
and the second port of the first switching valve, the first port of
the second switching valve and the third port of the second
switching valve, and the hydraulic actuator with one another.
6. The hydraulic control circuit according to claim 5, wherein the
predetermined condition is a condition that the control hydraulic
pressure is higher than or equal to a predetermined value.
7. The hydraulic control circuit according to claim 5, wherein the
predetermined condition is a condition that the control hydraulic
pressure is lower than a predetermined value.
8. The hydraulic control circuit according to claim 1, wherein the
three oil paths include an oil path that supplies a source pressure
to hydraulic oil for actuating the hydraulic actuator, an oil path
that supplies the control hydraulic pressure, and an oil path that
communicates with a port exposed to an atmosphere.
9. The hydraulic control circuit according to claim 1, wherein a
source pressure of a hydraulic oil is input to the third port of
the first switching valve, and an atmosphere exposure oil path is
connected to one of the second port of the second, switching valve
and the third port of the second switching valve, to which the
control hydraulic pressure is not input.
Description
INCORPORATION BY REFERENCE
[0001] The disclosure of Japanese Patent Applications No.
2013-239373 and 2014-217830 filed on Nov. 19, 2013 and Oct. 24,
2014 including the specification, drawings and abstract is
incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a technique for setting three oil
paths with the use of two switching valves.
[0004] 2. Description of Related Art
[0005] There is well known a hydraulic control circuit that
alternatively switches by a switching valve between an oil path
that supplies hydraulic oil to a hydraulic actuator and an oil path
that drains hydraulic oil from the hydraulic actuator. For example,
a hydraulic control device for an automatic transmission, described
in Japanese Patent Application Publication No. 6-174079 (JP
6-174079 A) is such a hydraulic control circuit. JP 6-174079 A
describes the hydraulic control device including two oil paths that
communicate with a clutch via a switching valve that is actuated by
a solenoid valve. When supply of hydraulic pressure via one of the
oil paths fails, the hydraulic control device switches the oil path
communicating with the clutch to the other one of the oil paths by
the switching valve.
SUMMARY OF THE INVENTION
[0006] Incidentally, if three oil paths communicating with the
clutch are respectively assigned to, for example, supply of source
pressure of hydraulic oil, supply of control pressure of hydraulic
oil, and release of hydraulic oil to an atmosphere, it is
conceivable to provide two switching valves for alternatively
switching among the oil paths and two solenoid valves for
independently actuating these switching valves. In this case, one
of each of a switching valve and a solenoid valve is added to the
configuration including the two oil paths communicating with the
clutch, so there is an inconvenience that the size of the hydraulic
control device increases.
[0007] The invention provides a hydraulic control circuit for a
drive line, which is able to suppress an increase in the size of a
device when three oil paths communicating with a hydraulic actuator
are set with the use of two switching valves.
[0008] An aspect of the invention provides a hydraulic control
circuit for a drive line. The hydraulic control circuit includes a
first switching valve, a second switching valve, a first solenoid
valve and a second solenoid valve. The first switching valve is
configured to be alternatively switched by a switching hydraulic
pressure so as to connect any two of a first port, a second port
and a third port. The first port of the first switching valve is
connected to a hydraulic actuator. The second switching valve is
configured to be alternatively switched by the switching hydraulic
pressure so as to connect any two of a first port, a second port
and a third port. The first port of the second switching valve is
connected to the second port of the first switching valve. The
first solenoid valve is provided in common to the first switching
valve and the second switching valve. The first solenoid valve is
configured to supply the switching hydraulic pressure to the first
switching valve and the second switching valve. The second solenoid
valve is configured to regulate a hydraulic pressure as a control
hydraulic pressure. The hydraulic pressure is supplied to the
hydraulic actuator. Any one of three oil paths is communicated with
the hydraulic actuator by supplying the control hydraulic pressure
from the second solenoid valve to the hydraulic actuator via any
one of the third port of the first switching valve, the second port
of the second switching valve and the third port of the second
switching valve and supplying the switching hydraulic pressure from
the first solenoid valve to at least one of the first switching
valve or the second switching valve.
[0009] With this configuration, the hydraulic control circuit
according to the aspect of the invention is able to alternatively
switch among the three oil paths communicating with the hydraulic
actuator by providing the single solenoid valve that actuates the
two switching valves when any one of the three oil paths
communicating with the hydraulic actuator is set with the use of
the two switching valves.
[0010] In the hydraulic control circuit according to the above
aspect, the three oil paths may include a first oil path, a second
oil path and a third oil path. When the predetermined switching
hydraulic pressure is output and the control hydraulic pressure
does not satisfy a predetermined condition, the first oil path may
be set by communicating the first port and second port of the first
switching valve, the first port and second port of the second
switching valve and the hydraulic actuator with one another. When
the predetermined switching hydraulic pressure is not output and
the control hydraulic pressure does not satisfy the predetermined
condition, the second oil path may be set by communicating the
first port and third port of the first switching valve with the
hydraulic actuator. When the predetermined switching hydraulic
pressure is output and the control hydraulic pressure satisfies the
predetermined condition, the third oil path may be set by
communicating the first port and second port of the first switching
valve, the first port and third port of the second switching valve
and the hydraulic actuator with one another. With this
configuration, it is possible to alternatively switch among the
three oil paths by a combination of the switching hydraulic
pressure common to the two switching valves with the predetermined
condition of the control hydraulic pressure.
[0011] In the hydraulic control circuit according to the above
aspect, the three oil paths may include a first oil path, a second
oil path and a third oil path. When the predetermined switching
hydraulic pressure is output and the control hydraulic pressure
does not satisfy a predetermined condition, the first oil path may
be set by communicating the first port and second port of the first
switching valve, the first port and second port of the second
switching valve and the hydraulic actuator with one another. When
the predetermined switching hydraulic pressure is not output and
the control hydraulic pressure does not satisfy the predetermined
condition, the second oil path may be set by communicating the
first port and third port of the first switching valve with the
hydraulic actuator. When the predetermined switching hydraulic
pressure is output and the control hydraulic pressure satisfies the
predetermined condition, the third oil path may be set by
communicating the first port and second port of the first switching
valve, the first port and third port of the second switching valve
and the hydraulic actuator with one another. With this
configuration, it is possible to alternatively switch among the
three oil paths by a combination of the switching hydraulic
pressure common to the two switching valves with the predetermined
condition of the control hydraulic pressure.
[0012] In the hydraulic control circuit according to the above
aspect, the three oil paths may include an oil path that supplies a
source pressure to hydraulic oil for actuating the hydraulic
actuator, an oil path that supplies the control hydraulic pressure,
and an oil path that communicates with a port exposed to an
atmosphere. With this configuration, it is possible to
alternatively communicate the oil paths having three different
functions with the hydraulic actuator.
[0013] In the hydraulic control circuit according to the above
aspect, the predetermined condition may be a condition that the
control hydraulic pressure is higher than or equal to a
predetermined value. With this configuration, when the control
hydraulic pressure is higher than or equal to the predetermined
value, it is possible to switch into the third oil path.
[0014] In the hydraulic control circuit according to the above
aspect, the predetermined condition may be a condition that the
control hydraulic pressure is lower than a predetermined value.
With this configuration, when the control hydraulic pressure is
lower than the predetermined value, it is possible to switch into
the third oil path.
[0015] In the hydraulic control circuit according to the above
aspect, a source pressure of the hydraulic oil may be input to the
third port of the first switching valve, and an atmosphere exposure
oil path may be connected to one of the second and third ports of
the second switching valve, to which the control hydraulic pressure
is not input. With this configuration, it is possible to
alternatively switch among the oil path that supplies the source
pressure, the oil path that supplies the control hydraulic pressure
and the atmosphere exposure oil path. As a result, for example,
when the second solenoid valve is in off-fail where the control
hydraulic pressure is not output or only a low hydraulic pressure
is output, the source pressure of hydraulic oil is supplied to the
hydraulic actuator. For example, by communicating the hydraulic
actuator with the atmosphere exposure oil path, hydraulic oil in
the hydraulic actuator is more quickly drained than hydraulic oil
in the hydraulic actuator is drained via the second solenoid valve,
so the hydraulic pressure in the hydraulic actuator is quickly
reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Features, advantages, and technical and industrial
significance of exemplary embodiments of the invention will be
described below with reference to the accompanying drawings, in
which like numerals denote like elements, and wherein:
[0017] FIG. 1 is a view that illustrates the schematic
configuration of a drive line provided in a vehicle to which the
invention is applied, and is a view that illustrates a relevant
portion of control functions and control system in the vehicle;
[0018] FIG. 2 is a view that illustrates the schematic
configuration of a K0 hydraulic control circuit associated with
actuation of a clutch within a hydraulic control circuit;
[0019] FIG. 3 is a view that shows an example embodiment of the K0
hydraulic control circuit;
[0020] FIG. 4 is a table that shows an example of a K0 clutch
pressure summarized for each condition;
[0021] FIG. 5 is a table that shows a K0 clutch pressure during
off-fail of a solenoid valve, summarized for each condition;
[0022] FIG. 6 is a flowchart that illustrates a relevant portion of
control operations of an electronic control unit, that is, control
operations for engaging the clutch during off-fail of the solenoid
valve;
[0023] FIG. 7 is an example of a time chart in the case where the
control operations shown in the flowchart of FIG. 6 are
executed;
[0024] FIG. 8 is a flowchart that illustrates a relevant portion of
control operations of the electronic control unit, that is, control
operations for rapidly releasing the K0 clutch pressure;
[0025] FIG. 9 is an example of a time chart in the case where the
control operations shown in the flowchart of FIG. 8 are
executed;
[0026] FIG. 10 is a view that shows another example embodiment of
the K0 hydraulic control circuit;
[0027] FIG. 11 is a view that shows another example embodiment of
the K0 hydraulic control circuit;
[0028] FIG. 12 is a view that shows another example embodiment of
the K0 hydraulic control circuit;
[0029] FIG. 13 is a view that shows another example embodiment of
the K0 hydraulic control circuit;
[0030] FIG. 14 is a table that shows another example of the K0
clutch pressure summarized for each condition;
[0031] FIG. 15 is a view that shows another example embodiment of
the K0 hydraulic control circuit;
[0032] FIG. 16 is a view that shows another example embodiment of
the K0 hydraulic control circuit; and
[0033] FIG. 17 is a table that shows another example of the K0
clutch pressure summarized for each condition.
DETAILED DESCRIPTION OF EMBODIMENTS
[0034] In an embodiment of the invention, suitably, a drive line is
provided in a vehicle, and constitutes a power transmission path
from a driving force source to a drive wheel. A hydraulic actuator
is, for example, an actuator that constitutes part of a hydraulic
engagement device that connects or interrupts the power
transmission path. The hydraulic engagement device is, for example,
a hydraulic clutch that connects or interrupts the power
transmission path between an engine, which serves as the driving
force source, and the drive wheel, that is, a hydraulic clutch that
is able to disconnect the engine from the drive wheel. The engine
is, for example, an internal combustion engine, such as a gasoline
engine and a diesel engine, which generates power through
combustion of fuel.
[0035] Suitably, the vehicle is a hybrid vehicle in which an
electric motor that functions as a driving force source is provided
in the power transmission path between the engine and the drive
wheel. The hydraulic clutch connects or interrupts a power
transmission path between the engine and the electric motor. The
thus configured hybrid vehicle carries out engine running in which
the hybrid vehicle travels by using at least the engine as the
driving force source in a state where the clutch is engaged, and
carries out motor running in which the hybrid vehicle travels by
using only the electric motor as the driving force source in a
state where the clutch is released. When the engine is started up
during the motor running, the engine is cranked by the electric
motor by controlling the clutch toward engagement.
[0036] Suitably, the vehicle includes a transmission that
constitutes part of the power transmission path between the driving
force source and the drive wheel. The transmission is a manual
transmission, such as a known synchromesh parallel-two-shaft
transmission including a plurality of pairs of constant-mesh
transmission gears between the two shafts, various automatic
transmissions (a planetary gear automatic transmission, a
synchromesh parallel-two-shaft automatic transmission, a DCT, A
continuously variable transmission, such as a belt-type
continuously variable transmission, or the like), or the like. Each
of the automatic transmissions is formed of an automatic
transmission alone, an automatic transmission including a fluid
transmission device, an automatic transmission including an
auxiliary transmission, or the like.
[0037] Hereinafter, a first embodiment of the invention will be
described in detail with reference to the accompanying
drawings.
[0038] FIG. 1 is a view that illustrates the schematic
configuration of a drive line 12 provided in a vehicle 10 to which
the invention is applied and is a view that illustrates a relevant
portion of control functions and control system for various
controls in the vehicle 10. In FIG. 1, the vehicle 10 is a hybrid
vehicle that includes an engine 14 and an electric motor MG as
driving force sources. The drive line 12 includes an engine
separating clutch K0 (hereinafter, referred to as clutch K0), a
torque converter 18, an automatic transmission 20, and the like, in
order from the engine 14 side inside a transmission case 16. The
transmission case 16 serves as a non-rotating member. The drive
line 12 includes a propeller shaft 24, a differential gear 26, a
pair of axles 28, and the like. The propeller shaft 24 is coupled
to a transmission output shaft 22 that is an output rotating member
of the automatic transmission 20. The differential gear 26 is
coupled to the propeller shaft 24. The pair of axles 28 are coupled
to the differential gear 26. A pump impeller 18a of the torque
converter 18 is coupled to an engine coupling shaft 30 via the
clutch K0. The pump impeller 18a is directly coupled to the
electric motor MG. A turbine impeller 18b of the torque converter
18 is directly coupled to a transmission input shaft 32 that is an
input rotating member of the automatic transmission 20. The thus
configured drive line 12 is, for example, suitably used in the FR
vehicle 10. In the drive line 12, the power (which is synonymous
with torque and force unless otherwise specifically distinguished
from each other) of the engine 14 is transmitted from the engine
coupling shaft 30 to a pair of drive wheels 34 sequentially via the
clutch K0, the torque converter 18, the automatic transmission 20,
the propeller shaft 24, the differential gear 26, the pair of axles
28, and the like, when the clutch K0 is engaged. The engine
coupling shaft 30 couples the engine 14 to the clutch K0. In, this,
way, the drive line 12 constitutes a power transmission path from
the engine 14 to the drive wheels 34.
[0039] The vehicle 10, for example, includes a mechanical oil pump
36, an inverter 38, an electrical storage device 40, a hydraulic
control circuit 50, and the like. The oil pump 36 is coupled to the
pump impeller 18a. The inverter 38 controls the operation of the
electric motor MG. The electrical storage device 40 exchanges
electric power with the electric motor MG via the inverter 38. The
hydraulic control circuit 50 controls shift operation of the
automatic transmission 20, engagement/release operation of the
clutch K0 and engagement/release operation of a known lockup clutch
provided in the torque converter 18. The oil pump 36 generates the
source pressure of hydraulic oil (that is, operating hydraulic
pressure for carrying out shift control over the automatic
transmission 20, engagement/release control over the clutch K0,
engagement/release control over the lockup clutch, and the like)
that is supplied to the hydraulic control circuit 50 by being
rotationally driven by the engine 14 and/or the electric motor
MG.
[0040] The electric motor MG is a so-called motor generator having
the function of a motor that generates mechanical power from
electric energy and the function of a generator that generates
electric energy from mechanical energy. The electric motor MG
generates driving power by using electric power (which is
synonymous with electric energy unless otherwise specifically
distinguished from each other) that is supplied from the electrical
storage device 40 via the inverter 38 instead of the engine 14 or
in addition to the engine 14. The electric motor MG converts the
power of the engine. 14 or driven force, which is input from the
drive wheels 34 side, to electric power through regeneration, and
stores the electric power in the electrical storage device 40 via
the inverter 38. The electric motor MG is provided in the power
transmission path between the engine 14 and the drive wheels 34,
and is coupled to a power transmission path between the clutch K0
and the torque converter 18. Power is transmitted to each other
between the electric motor MG and the pump impeller 18a. In this
way, the electric motor MG is coupled to the transmission input
shaft 32 of the automatic transmission 20 such that power is
transmittable without passing through the clutch K0.
[0041] The clutch K0 is, for example, a wet-type multi-disc
hydraulic friction engagement device. The clutch K0 undergoes
engagement/release control from the hydraulic control circuit 50 by
using hydraulic pressure that is generated by the oil pump 36 as a
source pressure. In the engagement/release control, a torque
capacity (hereinafter, referred to as K0 torque) of the clutch K0
is changed by regulating a solenoid valve, or the like, in the
hydraulic control circuit 50. In the engaged state of the clutch
K0, the pump impeller 18a and the engine 14 are integrally rotated
via the engine coupling shaft 30. On the other hand, in a released
state of the clutch K0, transmission of power between the engine 14
and the pump impeller 18a is interrupted. That is, the engine 14
and the drive wheels 34 are disconnected from each other by
releasing the clutch K0. Because the electric motor MG is coupled
to the pump impeller 18a, the clutch K0 also functions as a clutch
that is provided in the power transmission path between the engine
14 and the electric motor MG and that connects or interrupts the
power transmission path, that is, a clutch that connects the engine
14 to the electric motor MG or disconnects the engine 14 from the
electric motor MG.
[0042] FIG. 2 is a view that illustrates the schematic
configuration of the K0 hydraulic control circuit 52 associated
with actuation of the clutch K0 within the hydraulic control
circuit 50. In FIG. 2, the oil pump 36 draws hydraulic oil,
returned to an oil pan 54, via a suction port (strainer) 56 and
then discharges the hydraulic oil to a discharge oil path 58. The
discharge oil path 58 is coupled to an oil path within the
hydraulic control circuit 50 (for example, a line pressure oil path
60 through which a line pressure PL is applied). The hydraulic
control circuit 50 includes a primary regulator valve 62. The
primary regulator valve 62 regulates the line pressure PL by using
the operating hydraulic pressure as a source pressure. The
operating hydraulic pressure is output (generated) from the oil
pump 36. The K0 hydraulic control circuit 52 that constitutes part
of the hydraulic control circuit 50, for example, controls
engagement/release operation of the clutch K0 by using the line
pressure PL as a source pressure. In this way, the line pressure PL
is the source pressure of hydraulic oil that is supplied to or
drained from a hydraulic actuator 64. The hydraulic actuator 64 is
formed of a clutch drum, a clutch piston, and the like, and is part
of the clutch K0. The K0 hydraulic control circuit 52 includes a
solenoid valve SLK0 (hereinafter, referred to as solenoid valve
66). The solenoid valve 66 outputs a control hydraulic pressure
Pslk0 (hereinafter, referred to as SLK0 pressure Pslk0) by
regulating the pressure of hydraulic oil that is supplied to the
clutch K0. The thus configured K0 hydraulic control circuit 52
controls engagement/release operation of the clutch K0 by
controlling supply or drain of hydraulic oil for actuation
associated with the clutch K0 via the solenoid valve 66. Hydraulic
oil, or the like, that is drained as a result of operation of the
solenoid valve 66 is returned to the oil pan 54 via a drain oil
path 68.
[0043] Referring back to FIG. 1, the vehicle 10 includes, for
example, an electronic control unit 70. The electronic control unit
70 includes a controller for the vehicle 10 associated with
actuation of the clutch K0, and the like. The electronic control
unit 70 is, for example, configured to include a so-called
microcomputer including a CPU, a RAM, a ROM, an input/output
interface, and the like. The CPU executes various controls over the
vehicle 10 by carrying out signal processing in accordance with a
program prestored in the ROM while utilizing the temporary storage
function of the RAM. For example, the electronic control unit 70 is
configured to execute output control over the engine 14, drive
control over the electric motor MG; including regenerative control
over the electric motor MG, shift control over the automatic
transmission 20, torque capacity control over the clutch K0, and
the like. The electronic control unit 70 is formed separately in a
unit for engine control, a unit for electric motor control, a unit
for hydraulic pressure control, and the like, as needed. Various
signals based on detected values of various sensors are supplied to
the electronic control unit 70. The various sensors, for example,
include various rotation speed sensors 72, 74, 76, 78, an
accelerator operation amount sensor 80, a battery sensor. 82, and
the like. The various signals, for example, include an engine
rotation speed Ne, a turbine rotation speed Nt, that is, a
transmission input shaft rotation speed Nin, a transmission output
shaft rotation speed Nout corresponding to a vehicle speed V, an
electric motor rotation speed (MG rotation speed) Nm, an
accelerator, operation amount .theta.acc that corresponds to a
driver's drive request amount to, the vehicle 10, a state of charge
(level of charge) SOC of the electrical storage device 40, and the
like. For example, an engine output control command signal Se for
output control over the engine 14, an electric motor control
command signal Sm for controlling the operation of the electric
motor MG, hydraulic pressure control command signals Sp for
operating the solenoid valve 66, and the like, included in the
hydraulic control circuit 50 for controlling the hydraulic actuator
64 of the clutch K0, the hydraulic actuator of the automatic
transmission 20, the lockup clutch, and the like, are respectively
output from the electronic control unit 70 to an engine control
device, such as a throttle actuator and a fuel injection device,
the inverter 38, the hydraulic control circuit 50, and the
like.
[0044] The electronic control unit 70 includes hybrid control
means, that is, a hybrid control unit 90, in order to implement
control functions for various controls in the vehicle 10. The
hybrid control unit 90 has the function of an engine drive control
unit that executes drive control over the engine 14 and the
function of an electric motor operation control unit that controls
the operation of the electric motor MG as a driving force source or
a generator via the inverter 38, and executes hybrid drive control,
or the like, with the use of the engine 14 and the electric motor
MG through those control functions. For example, the hybrid control
unit 90 calculates a required driving torque Tdtgt as the driver's
drive request amount for the vehicle 10 on the basis of the
accelerator operation amount acc and the vehicle speed V. In
consideration of a transmission loss, an auxiliary load, the speed
ratio .gamma. of the automatic transmission 20, the level of charge
SOC of the electrical storage device 40, and the like, the hybrid
control unit 90 outputs the command signals (the engine output
control command signal Se and the electric motor control command
signal Sm) for controlling the driving force sources so as to
obtain the outputs of the driving force sources (the engine 14 and
the electric motor MG), which achieve the required driving torque
Tdtgt. Other than the required driving torque Tdtgt [Nm] of the
drive wheels 34, the drive request amount may be a required driving
force [N] of the drive wheels 34, a required driving power [W] of
the drive wheels 34, a required transmission output torque of the
transmission output shaft 22, or the like. The drive request amount
may also be merely the accelerator operation amount .theta.acc [%],
a throttle valve opening degree [%], an intake air amount [g/sec],
or the like.
[0045] Specifically, for example, when the required driving torque
Tdtgt falls within the range in which the required driving torque
Tdtgt can be provided by only the output of the electric motor MG,
the hybrid control unit 90 sets a traveling mode to a motor running
mode (hereinafter, EV mode), and carries out motor running (EV
traveling) in which the vehicle travels by using only the electric
motor MG as the driving force source in a state where the clutch K0
is released. On one hand, for example, when the required driving
torque Tdtgt falls within the range in which the required driving
torque Tdtgt cannot be provided unless at least the output of the
engine 14 is used, the hybrid control unit 90 sets the traveling
mode to an engine running mode, that is, a hybrid traveling mode
(hereinafter, HV mode), and carries out engine running, that is,
hybrid traveling (HV traveling) in which the vehicle travels by
using at least the engine 14 as the driving force source in a state
where the clutch K0 is engaged. On the other hand, for example,
even when the required driving torque Tdtgt falls within the range
in which the required driving torque Tdtgt can be provided by only
the output of the electric motor MG, but when warm-up of the engine
14 or device associated with the engine 14 is required, the hybrid
control unit 90 carries out HV traveling. In this way, the hybrid
control unit 90 switches between EV traveling and HV traveling by
automatically stopping the engine 14 during engine running or
restarting the engine 14 after an engine stop on the basis of the
required driving torque Tdtgt, or the like.
[0046] When the hybrid control unit 90 determines that there is an
engine starting request as a result of, for example, an increase in
the required driving torque Tdtgt during EV traveling, necessity of
engine warm-up, or the like, the hybrid control unit 90 executes
the series of operations associated with start-up of the engine 14.
Specifically, when the hybrid control unit 90 determines that there
is an engine starting request, the hybrid control unit 90 cranks
the engine 14 with the use of the electric motor MG by controlling
the released clutch K0 toward engagement. In addition, the hybrid
control unit 90 starts up the engine 14 by starting supply of fuel,
engine ignition, and the like (which is synonymous with a restart
unless otherwise specifically distinguished from each other) in
interlocking with cranking of the engine 14 with the use of the
electric motor MG. Subsequently, when the hybrid control unit 90
determines that the engine 14 has carried out complete explosion
(that is, the engine 14 enters a state where the engine 14 is
autonomously rotatable), the hybrid control unit 90 controls the
clutch K0, which has been controlled toward engagement, toward
release once. That is, the hybrid control unit 90 increases the
engine rotation speed Ne by controlling the clutch K0 toward
engagement until the engine 14 carries out complete explosion, and,
after the engine 14 has carried out complete explosion, the engine
rotation speed Ne is increased through autonomous operation of the
engine 14. For example, when the engine rotation speed Ne has
increased to the MG rotation speed Nm through autonomous operation
of the engine 14, the hybrid control unit 90 quickly completely
engages the clutch K0. With such an engine starting method, because
the clutch K0 is engaged in a state where the differential rotation
of the clutch K0 itself is suppressed, an engagement shock is
suppressed even when the clutch K0 is quickly engaged.
[0047] When the solenoid valve 66 is in off-fail where no SLK0
pressure Pslk0 that is the control hydraulic pressure Pslk0 of the
solenoid valve 66 is output or only a hydraulic pressure lower than
an SLK0 command pressure that is a command value to the solenoid
valve 66 is output, there is a possibility that the vehicle 10
cannot carry out appropriate engine running in which the vehicle
travels in a state where the clutch K0 is completely engaged and
the vehicle 10 is allowed to carry out only EV traveling and, as a
result, the travel distance of the vehicle 10 is limited. When the
solenoid valve 66 is in off-fail, for example, it is conceivable to
supply the line pressure PL to the clutch K0 and the vehicle 10
carries out engine running by completely engaging the clutch K0.
Aside from this, in the above-described engine starting method,
when the clutch K0, which has been controlled toward engagement, is
temporarily controlled toward release, it is desirable that the
clutch K0 be quickly released. For example, if the clutch K0 is
released via the solenoid valve 66, responsiveness can be
insufficient. Particularly, when a vibration damping accumulator,
or the like, is provided, there is a possibility that
responsiveness deteriorates. At the time of such release of the
clutch K0, for example, it is conceivable that, by draining the
hydraulic oil via an atmosphere exposure oil path EX, hydraulic oil
in the hydraulic actuator 64 is more quickly drained than the
hydraulic oil is drained via the solenoid valve 66. The atmosphere
exposure oil path EX is able to drain hydraulic oil in a larger
amount than a drain oil path EXslk0 of the solenoid valve 66.
[0048] Therefore, the hydraulic control circuit 50 according to the
present, embodiment includes three oil paths as oil paths
communicating with the hydraulic actuator 64. One of the oil paths
supplies the SLK0 pressure Pslk0 to the hydraulic actuator 64.
Another one of the oil paths supplies the line pressure PL to the
hydraulic actuator 64. The other one of the oil paths connects the
atmosphere exposure oil path EX to the hydraulic actuator 64 in
order to drain hydraulic oil in the hydraulic actuator 64. The
hydraulic control circuit 50 alternatively switches among those
three oil paths. Generally, three oil paths are formed by providing
two switching valves. Each of the switching valves is able to
switch between two oil paths. Two on-off solenoid valves are
respectively provided for the switching valves. Each of the on-off
solenoid valves outputs hydraulic pressure for actuating a
corresponding one of the switching valves. Thus, it is possible to
alternatively switch among the three oil paths. In contrast, in the
present embodiment, focusing on the fact that one of the three oil
paths is an oil path that supplies the SLK0 pressure Pslk0, it is
suggested that the two on-off solenoid valves be integrated into
one. That is, when the three oil paths communicating with the
hydraulic actuator 64 are set with the use of the two switching
valves, the hydraulic control circuit 50 (K0 hydraulic control
circuit 52) according to the present embodiment alternatively
switches among the three oil paths including the oil path that
supplies the SLK0 pressure Pslk0 only by providing a single on-off
solenoid valve 104. Hereinafter, an example embodiment of the K0
hydraulic control circuit 52 will be described.
[0049] FIG. 3 is a view that shows the example embodiment of the K0
hydraulic control circuit 52. In FIG. 3, the K0 hydraulic control
circuit 52 further includes a first switching valve 100, a second
switching valve 102 and the on-off solenoid valve 104 in addition
to the solenoid valve 66 that outputs the SLK0 pressure Pslk0. The
first switching valve 100 and the second switching valve 102 are
valves having substantially the same configuration. Each of the
first switching valve 100 and the second switching valve 102
includes a spring SP, a first input port Pin1, a second input port
Pin2 and an output port Pout. The output port Pout alternatively
communicates with the first input port Pin1 or the second input
port Pin2. For example, each of the first switching valve 100 and
the second switching valve 102 includes a spool valve element. In a
valve body, the spool valve element is accommodated so as to be
slidable by a predetermined sliding stroke and is urged in one
direction by the spring SP. The spool valve element is formed of a
well-known spool valve element that alternatively communicates the
output port Pout with one or the other of the first input port Pin1
and the second input port Pin2 in accordance with movement of the
spool valve element to one end or the other end of the sliding
stroke.
[0050] The on-off solenoid valve 104 is a common on-off solenoid
valve that outputs a switching hydraulic pressure Pon. The
switching hydraulic pressure Pon is a predetermined switching
hydraulic pressure for actuating the two switching valves 100, 102.
The solenoid valve 66 is, for example, a normally-closed or NIC
linear solenoid valve. The solenoid valve 66 is set in an open
state in an excited state (on state) and outputs the SLK0 pressure
Pslk0 that continuously changes with the command value (SLK0
command pressure), or the solenoid valve 66 is set in a closed
state in a non-energized state (off state) and does not output
hydraulic pressure. The on-off solenoid valve 104 is, for example,
a normally-closed on-off solenoid valve. The on-off solenoid valve
104 outputs the switching hydraulic pressure Pon in an energized
state according to an on command, or does not output the switching
hydraulic pressure Pon in a non-energized state according to an off
command. Each of the springs SP of the first and second switching
valves 100, 102 generates urging force for switching a
corresponding one of the first and second switching valves 100, 102
toward the off state to communicate the corresponding first input
port Pin1 with the corresponding output port Pout. The switching
hydraulic pressure Pon is applied to each of the first and second
switching valves 100, 102 so that thrust is generated for switching
each of the first and second switching valves 100, 102 against the
urging force of the corresponding spring SP in an opposite
direction to a direction in which thrust that is generated by the
urging force of the corresponding spring SP acts. The switching
hydraulic pressure Pon is a hydraulic pressure for switching each
of the first and second switching valves 100, 102 toward an on
state to communicate the corresponding second input port Pin2 with
the corresponding output port Pout.
[0051] In the present embodiment, in the K0 hydraulic control
circuit 52, the output port Pout of the first switching valve 100
is connected to the hydraulic actuator 64. In the present
embodiment, the output port Pout of the second switching valve. 102
is connected to the first input port Pin1 of the first switching
valve 100, and the SLK0 pressure Pslk0 is input to the first input
port Pin1 of the second switching valve 102. In the present
embodiment, the first port of the first switching valve is the
output port Pout of the first switching valve 100, the second port
of the first switching valve is the first input port Pin1 of the
first switching valve 100, the third port of the first switching
valve is the second input port Pin2 of the first switching valve
100, the first port of the second switching valve is the output
port Pout of the second switching valve 102, and the second port or
third port of the second switching valve is one of the first input
port Pin1 and second input port Pin2 of the second switching valve
102. In the present embodiment, the first solenoid valve is the
on-off solenoid valve 104, and the second solenoid valve is the
solenoid valve 66. The SLK0 pressure Pslk0 is applied to the first
switching valve 100 so that thrust is generated for switching the
first switching valve 100 in an opposite direction (second
direction) to a direction (first direction) of thrust that is
generated by application of the switching hydraulic pressure
Pon.
[0052] In the thus configured K0 hydraulic control circuit 52, when
the SLK0 pressure Pslk0 does not satisfy a predetermined condition
while no switching hydraulic pressure Pon is output, the first
input port Pin1 is communicated with the output port Pout in each
of the first and second switching valves 100, 102. Thus, a first
oil path 106 is set. The first oil path 106 is an oil path that
communicates the first input port Pin1 of the second switching
valve 102, to which the SLK0 pressure Pslk0 is input, with the
hydraulic actuator 64 sequentially via the output port Pout of the
second switching valve 102, the first input port Pin1 of the first
switching valve 100 and the output port Pout of the first switching
valve 100, and is an, oil path that supplies the SLK0 pressure
Pslk0 to the hydraulic actuator 64 or releases the SLK0 pressure
Pslk0 from the hydraulic actuator 64.
[0053] The predetermined condition is a condition that the SLK0
pressure Pslk0 is higher than or equal to a predetermined value.
The predetermined value is a value that is set in the other
switching valve (the first switching valve 100 in the present
embodiment) on the basis of the urging force of the spring SP and
the thrust caused by the switching hydraulic pressure Pon
(=Pon.times.(Pressure receiving area of the spool valve element
(not shown)). The predetermined value is a value of the SLK0
pressure Pslk0 (hereinafter, referred to as switching valve
switching threshold) at a boundary at which communication of the
output port Pout with the first input port Pin1 or the second input
port Pin2 is switched depending on whether the thrust caused by the
SLK0 pressure Pslk0 is large or small. In the first switching valve
100 according to the present embodiment, when no switching
hydraulic pressure Pon is output, the first switching valve 100 is
switched to the off state where the first input port Pin1 is
communicated with the output port Pout depending on only the urging
force of the corresponding spring SE. Therefore, when no switching
hydraulic pressure Pon is output, the requirement that the SLK0
pressure Pslk0 does not satisfy the predetermined condition is not
required. That is, in the K0 hydraulic control circuit 52 according
to the present embodiment, when no switching hydraulic pressure Pon
is output, the first input port Pin1 is communicated with the
output port Pout in each of the first and second switching valves
100, 102 irrespective of the SLK0 pressure Pslk0. Thus, the first
oil path 106 is set.
[0054] In the K0 hydraulic control circuit 52, when the SLK0
pressure Pslk0 does not satisfy the predetermined condition while
the switching hydraulic pressure Pon is output (for example, when
the SLK0 pressure Pslk0 is lower than the switching valve switching
threshold), the second input port Pin2 is communicated with the
output port Pout in each of the first and second switching valves
100, 102. Thus, a second oil path 108 is set. The second oil path
108 is an oil path that communicates the second input port Pin2 of
the first switching valve 100 with the hydraulic actuator 64 via
the output port Pout of the first switching valve 100. In the
present embodiment, because the line pressure PL is input to the
second input port Pin2 of the first switching valve 100, the second
oil path 108 is an oil path that supplies the line pressure PL to
the hydraulic actuator 64.
[0055] In the K0 hydraulic control circuit 52, the first input port
Pin1 is communicated with the output port Pout in the first
switching valve 100 when the SLK0 pressure Pslk0 is higher than or
equal to the switching valve switching threshold irrespective of
whether the switching hydraulic pressure Pon is output, and the
second input port Pin2 is communicated with the output port Pout in
the second switching valve 102 depending on the fact that the
switching hydraulic pressure Pon is output. Thus, a third oil path
110 is set. The third oil path 110 is an oil path that communicates
the second input port Pin2 of the second switching valve 102 with
the hydraulic actuator 64 sequentially via the output port Pout of
the second switching valve 102, the first input port Pin1of the
first switching valve 100 and the output port Pout of the first
switching valve 100. In the present embodiment, because the
atmosphere exposure oil path EX is connected to the second input
port Pin2 of the second switching valve 102; which is one of the
first and second input ports Pin1, Pin2 of the second switching
valve 102, to which the SLK0 pressure Pslk0 is not input, the third
oil path 110 is an oil path that connects the atmosphere exposure
oil path EX to the hydraulic actuator 64.
[0056] FIG. 4 is a table that is a summary of the hydraulic
pressure that is supplied to the clutch K0 (K0 clutch pressure Pk0)
for each condition. As shown in FIG. 4, the K0 hydraulic control
circuit 52 is able to set three types of supply pressure (K0 clutch
pressure Pk0) with the use of the single on-off solenoid valve 104
by switching the first and second switching valves 100, 102 in
accordance with whether the SLK0 pressure Pslk0 is high or low (for
example, high or low with respect to the switching valve switching
threshold). Specifically, when no switching hydraulic pressure Pon
is output, the clutch K0 is controlled by the SLK0 pressure Pslk0.
When the switching hydraulic pressure Pon is output, the oil path
is switched in accordance with whether the SLK0 pressure Pslk0 is
high or low. The oil path is connected to the atmosphere exposure
oil path EX when the SLK0 pressure Pslk0 is high. The oil path is
supplied with the line pressure PL when the SLK0 pressure Pslk0 is
low. Thus, when the SLK0 pressure Pslk0 is low, it is possible to
supply the line pressure PL by outputting the switching hydraulic
pressure Pon. Because the SLK0 pressure Pslk0 is low when the
solenoid valve 66 is in off-fail, when it is determined that the
solenoid valve 66 is in off-fail, the line pressure PL is supplied
when the switching hydraulic pressure Pon is output, as shown in
FIG. 5. Thus, it is possible to engage the clutch K0 when the
solenoid valve 66 is in off-fail, so it is possible to carry out
engine running when the clutch K0 is engaged by outputting the
switching hydraulic pressure Pon. When the SLK0 pressure Pslk0 is
high, it is possible to connect the oil path to the atmosphere
exposure oil path EX by outputting the switching hydraulic pressure
Pon. When the SLK0 pressure Pslk0 is high because of a delay in
response at the time of release of the clutch K0, it is possible to
rapidly releasing the K0 clutch pressure Pk0 by connecting the oil
path to the atmosphere exposure oil path EX. When the SLK0 pressure
Pslk0 is high, the oil path is rapidly released through the
atmosphere exposure oil path EX. When the SLK0 pressure Pslk0 is
sufficiently low, it is less necessary to release the K0 clutch
pressure Pk0 through the atmosphere exposure oil path EX. However,
when the oil path is connected to the atmosphere exposure oil path
EX, the output of the switching hydraulic pressure Pon needs to be
stopped before the SLK0 pressure Pslk0 becomes lower than the
switching valve switching threshold. This is because, if the SLK0
pressure Pslk0 becomes lower than the switching valve switching
threshold in a state where the switching hydraulic pressure Pon is
output, there is a concern that the oil path is switched to supply
the line pressure PL and, as a result, the clutch K0 is engaged on
the contrary.
[0057] Referring back to FIG. 1, the electronic control unit 70
further includes oil path switching determination means, that is,
an oil path switching determination unit 92, in order to implement
control functions for various controls in the vehicle 10. The oil
path switching determination unit 92 determines whether to switch
the oil path by, for example, determining whether the solenoid
valve 66 is in off-fail. For example, in the case where the clutch
K0 is not engaged when the SLK0 command pressure for engaging the
clutch K0 is output by the hybrid control unit 90 and the
differential rotation speed of the clutch K0 itself does not become
zero or a value close to zero even with a lapse of a predetermined
time, the oil path switching determination unit 92 determines that
the SLK0 pressure Pslk0 according to the SLK0 command pressure is
not output, and determines that the solenoid valve 66 is in
off-fail. When the oil path switching determination unit 92
determines that the solenoid valve 66 is in off-fail, the hybrid
control unit 90 switches the oil path communicating with the
hydraulic actuator 64 from the oil path that supplies or releases
the SLK0 pressure Pslk0 to the oil path that supplies the line
pressure PL by outputting, to the on-off solenoid valve 104, a
command to output the switching hydraulic pressure Pon.
[0058] The oil path switching determination unit 92 determines
whether to switch the oil path by, for example, determining whether
rapid release of the K0 clutch pressure Pk0 is required. For
example, when the hybrid control unit 90 outputs the SLK0 command
pressure for releasing the clutch K0 and, for example, when the
release is a temporal release of the clutch K0 in process of engine
start-up or when the oil temperature is low, the oil path switching
determination unit 92 determines that rapid release of the K0
clutch pressure Pk0 is required. When the oil path switching
determination unit 92 determines that rapid release of the K0
clutch pressure Pk0 is required, the hybrid control unit 90
switches the oil path communicating with the hydraulic actuator 64
from the oil path that supplies or releases the SLK0 pressure Pslk0
to the oil path that connects the atmosphere exposure oil path EX
by outputting, to the on-off solenoid valve 104, the command to
output the switching hydraulic pressure Pon.
[0059] The oil path switching determination unit 92 determines
whether to switch the oil path by, for example, determining whether
an actual pressure of the SLK0 pressure Pslk0 has decreased to an
on-off solenoid valve switching control threshold. For example,
when the hybrid control unit 90 outputs the SLK0 command pressure
for releasing the clutch K0 and outputs, to the on-off solenoid
valve 104, the command to output the switching hydraulic pressure
Pon, and when a predetermined time has elapsed after the SLK0
command pressure is output, the oil path switching determination
unit 92 determines that the actual pressure of the SLK0 pressure
Pslk0 has decreased to the on-off solenoid valve switching control
threshold. The on-off solenoid valve switching control threshold is
a value obtained experimentally or by design in advance and stored
(that is, a predetermined value) that is higher by a predetermined
margin than the switching valve switching threshold in order to
avoid a situation that the SLK0 pressure Pslk0 becomes lower than
the switching valve switching threshold and the atmosphere exposure
oil path EX is switched over to the oil path that supplies the line
pressure PL. The predetermined time is, for example, a decrease
determination time determined in advance as a time from the output,
of the SLK0 command pressure for releasing the clutch K0 to when
the actual pressure of the SLK0 pressure Pslk0 decreases to the
on-off solenoid valve switching control threshold. The decrease
determination time may be a constant value or may be a value that
is changed on the basis of the magnitude of actual pressure of the
SLK0 pressure Pslk0, the oil temperature, or the like, at the
output start timing of the SLK0 command pressure. When the oil path
switching determination unit 92 determines that the actual pressure
of the SLK0 pressure Pslk0 has decreased to the on-off solenoid
valve switching control threshold, the hybrid control unit 90
switches the oil path communicating with the hydraulic actuator 64
from the oil path that connects the atmosphere exposure oil path EX
to the oil path that supplies or releases the SLK0 pressure Pslk0
by outputting, to the on-off solenoid valve 104, a command to stop
the output of the switching hydraulic pressure Pon.
[0060] FIG. 6 is a flowchart that illustrates a relevant portion of
control operations of the electronic control unit 70, that is,
control operations for engaging the clutch K0 when the solenoid
valve 66 is in off-fail. The flowchart is, for example, repeatedly
executed at an extremely short cycle time of about several
milliseconds to several tens of milliseconds. FIG. 7 is an example
of a time chart in the case where the control operations shown in
the flowchart of FIG. 6 are executed.
[0061] In FIG. 6, initially, in step (hereinafter, step is omitted)
S1 corresponding to the hybrid control unit 90, for example, the
SLK0 command pressure for engaging the clutch K0 is output.
Subsequently, in S2 corresponding to the oil path switching
determination unit 92, for example, it is determined whether the
solenoid valve 66 is in off-fail. When negative determination is
made in S2, the routine is ended. When affirmative determination is
made in S2, for example, the command to output the switching
hydraulic pressure Pon is output to the on-off solenoid valve 104
in S3 corresponding to the hybrid control unit 90. In combination
with the fact that the SLK0 pressure Pslk0 is lower than the
switching valve switching threshold because of off-fail of the
solenoid valve 66, the oil path communicating with the hydraulic
actuator 64 is switched from the oil path that supplies or releases
the SLK0 pressure Pslk0 to the oil path that supplies the line
pressure PL.
[0062] In FIG. 7, when the actual pressure of the SLK0 pressure
Pslk0 does not increase although the SLK0 command pressure for
engaging the clutch K0 is output, for example, it is determined on
the basis of the differential rotation speed of the clutch K0
itself that the solenoid valve 66 is in off-fail, and an off-fail
flag of the solenoid valve 66 is switched into an on state (t1
timing). The command to the on-off solenoid valve 104 is switched
to the on state, and the switching hydraulic pressure Pon is output
(after t1 timing). Thus, in combination with the fact that the
actual pressure of the SLK0 pressure Pslk0 is lower than the
switching valve switching threshold, the oil path that supplies the
line pressure PL is communicated with the hydraulic actuator 64,
and the clutch K0 is engaged.
[0063] FIG. 8 is a flowchart that illustrates a relevant portion of
control operations of the electronic control unit 70, that is,
control operations for rapidly releasing the K0 clutch pressure
Pk0. The flowchart is, for example, repeatedly executed at an
extremely short cycle time of about several milliseconds to several
tens of milliseconds. FIG. 9 is an example of a time chart in the
case where the control operations shown in the flowchart of FIG. 8
are executed.
[0064] In FIG. 8, initially, in S10 corresponding to the hybrid
control unit 90, for example, the SLK0 command pressure for
releasing the clutch K0 is output. Subsequently, in S20
corresponding to the oil path switching determination unit 92, for
example, it is determined whether rapid release of the K0 clutch
pressure Pk0 is required. When negative determination is made in
S20, the routine is ended. When affirmative determination is made
in S20, for example, the command to output the switching hydraulic
pressure Pon is output to the on-off solenoid valve 104 in S30
corresponding to the hybrid control unit 90. At the beginning of
release of the clutch K0, in combination with the fact that the
SLK0 pressure Pslk0 is higher than or equal to the switching valve
switching threshold, the oil path communicating with the hydraulic
actuator 64 is switched from the oil path that supplies or releases
the SLK0 pressure Pslk0 to the oil path that connects the
atmosphere exposure oil path EX. Subsequently, in S40 corresponding
to the oil path switching determination unit 92, for example, it is
determined whether the actual pressure of the SLK0 pressure Pslk0
has decreased to the on-off solenoid valve switching control
threshold. When negative determination is made in S40, S40 is
repeatedly executed. When affirmative determination is made in S40,
for example, the command to stop the output of the switching
hydraulic pressure Pon is output to the on-off solenoid valve 104
in S50 corresponding to the hybrid control unit 90. Thus, the oil
path communicating with the hydraulic actuator 64 is switched from
the oil path that connects the atmosphere exposure oil path EX to
the oil path that supplies or releases the SLK0 pressure Pslk0.
[0065] In FIG. 9, the SLK0 command pressure for releasing the
clutch K0 is output, the command to the on-off solenoid valve 104
is switched to the on state, and the switching hydraulic pressure
Pon is output (t1 timing). Thus, in combination with the fact that
the actual pressure of the SLK0 pressure Pslk0 is higher than or
equal to the switching valve switching threshold, the hydraulic
actuator 64 is communicated with the oil path that connects the
atmosphere exposure oil path EX, and the K0 clutch pressure Pk0 is
quickly decreased below the actual pressure of the SLK0 pressure
Pslk0. Subsequently, when the actual pressure of the SLK0 pressure
Pslk0 decreases to the on-off solenoid valve switching control
threshold, the command to the on-off solenoid valve 104 is switched
to the off state where the first input port Pin1 is communicated
with the output port Pout, and the output of the switching
hydraulic pressure Pon is stopped (t2 timing). Thus, the oil path
that supplies or releases the SLK0 pressure Pslk0 is communicated
with the hydraulic actuator 64, and a situation that the oil path
that supplies the line pressure PL is communicated with the
hydraulic actuator 64 as a result of the fact that the actual
pressure of the SLK0 pressure Pslk0 becomes lower than the
switching valve switching threshold is avoided. The oil path that
supplies or releases the SLK0 pressure Pslk0 is communicated with
the hydraulic actuator 64, so the K0 clutch pressure Pk0 increases
toward the actual pressure of the SLK0 pressure Pslk0. However, at
this timing, the SLK0 pressure Pslk0 has been already sufficiently
decreased, so influence on quick release of the clutch K0 is
small.
[0066] As described above, according to the present embodiment,
when the hydraulic control circuit 50 (K0 hydraulic control circuit
52) sets the three oil paths communicating with the hydraulic
actuator 64 with the use of the first and second switching valves
100, 102, the hydraulic control circuit 50 is able to alternatively
switch among the three oil paths communicating with the hydraulic
actuator 64, including the oil path that supplies the control
hydraulic pressure Pslk0 of the solenoid valve 66, by providing
only the single on-off solenoid valve 104 that actuates the first
and second switching valves 100, 102.
[0067] According to the present embodiment, by combining the
magnitude of thrust that is caused by the switching hydraulic
pressure Pon of the on-off solenoid valve 104 and applied to the
two switching valves, the magnitude of thrust caused by a pressure
other than the switching hydraulic pressure Pon, and the directions
of these thrust forces, it is possible to alternatively switch
among the three oil paths communicating with the hydraulic actuator
64 by providing only the single on-off solenoid valve 104 common to
the two switching valves.
[0068] According to the present embodiment, it is possible to
alternatively switch among the three oil paths with the use of a
combination of the switching hydraulic pressure Pon of the single
on-off solenoid valve 104 common to the two switching valves with
the predetermined condition of the control hydraulic pressure Pslk0
of the solenoid valve 66.
[0069] According to the present embodiment, when the predetermined
switching hydraulic pressure Pon is output, the control hydraulic
pressure Pslk0 of the solenoid valve 66 is higher than or equal to
the predetermined value and the control hydraulic pressure Pslk0 of
the solenoid valve 66 is applied in the second direction to switch
the second switching valve 102, the first input port Pin1 of the
first switching valve 100 is communicated with the output port Pout
of the second switching valve 102 and the second input port Pin2 of
the second switching valve 102 is communicated with the output port
Pout of the second switching valve 102. Thus, the third oil path
110 is set. As a result, it is possible to alternatively switch
among the three oil paths with the use of the single on-off
solenoid valve 104 common to the two switching valves.
[0070] According to the present embodiment, when the solenoid valve
66 is in off-fail, the line pressure PL is supplied to the
hydraulic actuator 64. By communicating the hydraulic actuator 64
with the atmosphere exposure oil path EX, hydraulic oil in the
hydraulic actuator 64 is more quickly drained than the hydraulic
oil in the hydraulic actuator 64 is drained via the solenoid valve
66. That is, the hydraulic pressure in the hydraulic actuator 64 is
quickly reduced.
[0071] Next, other embodiments of the invention will be described.
In the following description, like reference numerals denote
portions common to embodiments, and the description thereof is
omitted.
[0072] A second embodiment of the invention will be described. FIG.
10 is a view that shows another example embodiment of the K0
hydraulic control circuit 52, and is an embodiment different from
that of FIG. 3. Hereinafter, portions different from the embodiment
of FIG. 3 will be mainly described.
[0073] In FIG. 10, in the K0 hydraulic control circuit 52 according
to the present embodiment, the output port Pout of the second
switching valve 102 is connected to the second input port Pin2 of
the first switching valve 100. In the present embodiment, the SLK0
pressure Pslk0 is input to the first input port Pin1 of the first
switching valve 100. In the present embodiment, the first port of
the first switching valve is the output port Pout of the first
switching valve 100, the second port of the first switching valve
is the second input port Pin2 of the first switching valve 100, the
third port of the first switching valve is the first input port
Pin1 of the first switching valve 100, the first port of the second
switching valve is the output port Pout of the second switching
valve 102, and the second port or third port of the second
switching valve is one of the first input port Pin1 and second
input port Pin2 of the second switching valve 102. In the present
embodiment, the first solenoid valve is the on-off solenoid valve
104, and the second solenoid valve is the solenoid valve 66. In the
present embodiment, the SLK0 pressure Pslk0 is applied to the
second switching valve 102 so that thrust is generated for
switching the second switching valve 102 in the opposite direction
(second direction) to the direction (first direction) of thrust
that is generated by application of the switching hydraulic
pressure Pon.
[0074] In the thus configured K0 hydraulic control circuit 52
according to the present embodiment, when the SLK0 pressure Pslk0
does not satisfy the condition that the SLK0 pressure Pslk0 is
higher than or equal to the predetermined value while no, switching
hydraulic pressure Pon is output, the first input port Pin1 is
communicated with the output port Pout in each of the first and
second switching valves 100, 102. Thus, the first oil path 106 is
set. The first oil path 106 is an oil path that communicates the
first input port Pin1 of the first switching valve 100, to which
the SLK0 pressure Pslk0 is input, with the hydraulic actuator 64
via the output port Pout of the first switching valve 100, and is
an oil path that supplies the SLK0 pressure Pslk0 to the hydraulic
actuator 64 or releases the SLK0 pressure Pslk0 from the hydraulic
actuator 64. In the second switching valve 102 according to the
present embodiment, when no switching hydraulic pressure Pon is
output, the second switching valve 102 is switched to the off state
where the first input port Pin1 is communicated with the output
port Pout depending on only the urging force of the corresponding
spring SP. Therefore, when no switching hydraulic pressure Pon is
output, the requirement that the condition that the SLK0 pressure
Pslk0 is higher than or equal to the predetermined pressure is not
satisfied is not required. That is, in the K0 hydraulic control
circuit 52 according to the present embodiment, when no switching
hydraulic pressure Pon is output, the first input port Pin1 is
communicated with the output port Pout in each of the first and
second switching valves 100, 102 irrespective of the SLK0 pressure
Pslk0. Thus, the first oil path 106 is set.
[0075] In the K0 hydraulic control circuit 52 according to the
present embodiment, when the SLK0 pressure Pslk0 is lower than the
switching valve switching threshold while the switching hydraulic
pressure Pon is output, the second input port Pin2 is communicated
with the output port Pout in each of the first and second switching
valves 100, 102. Thus, the second oil path 108 is set. The second
oil path 108 is an oil path that communicates the second input port
Pin2 of the second switching valve 102 with the hydraulic actuator
64 sequentially via the output port Pout of the second switching
valve 102, the second input port Pin2 of the first switching valve
100 and the output port Pout of the first switching valve 100. In
the present embodiment, because the line pressure PL is input to
the second input port Pin2 of the second switching valve 102, the
second oil path 108 is an oil path that supplies the line pressure
PL to the hydraulic actuator 64.
[0076] In the K0 hydraulic control circuit, 52 according to the
present embodiment, the first input port Pin1 is communicated with
the output port Pout in the second switching valve 102 when the
SLK0 pressure Pslk0 is higher than or equal to the switching valve
switching threshold irrespective of whether the switching hydraulic
pressure Pon is output, and the second input port Pin2 is
communicated with the output port Pout in the first switching valve
100 depending on the fact that the switching hydraulic pressure Pon
is output. Thus, the third oil path 110 is set. The third oil path
110 is an oil path that communicates the first input port Pin1 of
the second switching valve 102 with the hydraulic actuator 64
sequentially via the output port Pout of the second switching valve
102, the second input port Pin2 of the first switching valve 100
and the output port Pout of the first switching valve 100. In the
present embodiment, because the atmosphere exposure oil path EX is
connected to the first input port Pin1 of the second switching
valve 102, the third oil path 110 is an oil path that connects the
atmosphere exposure oil path EX to the hydraulic actuator 64.
[0077] As described above, according to the present embodiment, as
shown in FIG. 4, the hydraulic control circuit 50 (K0 hydraulic
control circuit 52) is able to set three types of supply pressure
(K0 clutch pressure Pk0) with the use of the single on-off solenoid
valve 104 by switching the first and second switching valves 100,
102 in accordance with whether the SLK0 pressure Pslk0 is high or
low (for example, high or low with respect to the switching valve
switching threshold). Thus, similar advantageous effects to those
of the above-described first embodiment are obtained.
[0078] According to the present embodiment, when the predetermined
switching hydraulic pressure Pon is output, the control hydraulic
pressure Pslk0 of the solenoid valve 66 is higher than or equal to
the predetermined switching valve switching threshold and the
control hydraulic pressure Pslk0 of the solenoid valve 66 is
applied in the second direction to switch the second switching
valve 102, the second input port Pin2 of the first switching valve
100 is communicated with the output port Pout of the second
switching valve 102, and the first input port Pin1 of the second
switching valve 102 is communicated with the output port Pout of
the second switching valve 102. Thus, the third oil path 110 is
set. As a result, it is possible to alternatively switch among the
three oil, paths with the use of, the single on-off solenoid valve
104 common to the two switching valves.
[0079] A third embodiment of the invention will be described. FIG.
11 is a view that shows another example embodiment of the K0
hydraulic control circuit 52, and is an embodiment different from
that of FIG. 3. Hereinafter, portions different from the embodiment
of FIG. 3 will be mainly described.
[0080] In FIG. 11, in the K0 hydraulic control circuit 52 according
to the present embodiment, the output port Pout of the second
switching valve 102 is connected to the first input port Pin1 of
the first switching valve 100. In the present embodiment, the SLK0
pressure Pslk0 is input to the first input port Pin1 of the second
switching valve 102. In the present embodiment, the first port of
the first switching valve is the output port Pout of the first
switching valve 100, the second port of the first switching valve
is the first input port Pin1 of the first switching valve 100, the
third port of the first switching valve is the second input port
Pin2 of the first switching valve 100, the first port of the second
switching valve is the output port Pout of the second switching
valve 102, and the second port or third port of the second
switching valve is one of the first input port Pin1 and second
input port Pin2 of the second switching valve 102. In the present
embodiment, the first solenoid valve is the on-off solenoid valve
104, and the second solenoid valve is the solenoid valve 66. The
SLK0 pressure Pslk0 is applied to the other switching valve so that
thrust is generated for switching the other switching valve in the
same direction (first direction) as the direction (first direction)
of thrust that is generated by application of the switching
hydraulic pressure Pon. In the present embodiment, the SLK0
pressure Pslk0 is applied to the first switching valve 100 so that
thrust is generated for switching the first switching valve 100 in
the same direction (first direction) as the direction (first
direction) of thrust that is generated by application of the
switching hydraulic pressure Pon.
[0081] In the thus configured K0 hydraulic control circuit 52, when
the SLK0 pressure Pslk0 does not satisfy a predetermined condition
while no switching hydraulic pressure Pon is output, the first
input port Pin1 is communicated with the output port Pout in each
of the first and second switching valves 100, 102. Thus, the first
oil path 106 is set. The first oil path 106 is an oil path that
communicates the first input port Pin1 of the second switching
valve 102, to which the SLK0 pressure Pslk0 is input, with the
hydraulic actuator 64 sequentially via the output port Pout of the
second switching valve 102, the first input port Pin1 of the first
switching valve 100 and the output port Pout of the first switching
valve 100, and is an oil path that supplies the SLK0 pressure Pslk0
to the hydraulic actuator 64 or releases the SLK0 pressure Pslk0
from the hydraulic actuator 64.
[0082] The predetermined condition is a condition that the SLK0
pressure Pslk0 is lower than the predetermined value. When the
switching hydraulic pressure Pon is output and the SLK0 pressure
Pslk0 is higher than or equal to the predetermined value, the first
switching valve 100 according to the present embodiment is switched
to the on state where the second input port Pin2 is communicated
with the output port Pout. Therefore, in the first switching valve
100 according to the present embodiment, when no switching
hydraulic pressure Pon is output, the first switching valve 100 is
switched to the off state where the first input port Pin1 is
communicated with the output port Pout. Therefore, when no
switching hydraulic pressure Pon is output, the requirement that
the SLK0 pressure Pslk0 does not satisfy the predetermined
condition is not required. That is, in the K0 hydraulic control
circuit 52 according to the present embodiment, when no switching
hydraulic pressure Pon is output, the first input port Pin1 is
communicated with the output port Pout in each of the first and
second switching valves 100, 102 irrespective of the SLK0 pressure
Pslk0. Thus, the first oil path 106 is set.
[0083] In the K0 hydraulic control circuit 52, when the SLK0
pressure Pslk0 does not satisfy the predetermined condition while
the switching hydraulic pressure Pon is output (for example, when
the SLK0 pressure Pslk0 is higher than or equal to the switching
valve switching threshold), the second input port Pin2 is
communicated with the output port Pout in each of the first and
second switching valves 100, 102. Thus, the second oil path 108 is
set. The second oil path 108 is an oil path that communicates the
second input port Pin2 of the first switching valve 100 with the
hydraulic actuator 64 via the output port Pout of the first
switching valve 100. In the present embodiment, because the
atmosphere exposure oil path EX is connected to the second input
port Pin2 of the first switching valve 100, the second oil path 108
is an oil path that connects the atmosphere exposure oil path EX to
the hydraulic actuator 64.
[0084] In the K0 hydraulic control circuit 52 according to the
present embodiment, the first input port Pin1 is communicated with
the output port Pout in the first switching valve 100 when the SLK0
pressure Pslk0 is lower than the switching valve switching
threshold irrespective of whether the switching hydraulic pressure
Pon is output, and the second input port Pin2 is communicated with
the output port Pout in the second switching valve 102 depending on
the fact that the switching hydraulic pressure Pon is output. Thus,
the third oil path 110 is set. The third oil path 110 is an oil
path that communicates the second input port Pin2 of the second
switching valve 102 with the hydraulic actuator 64 sequentially via
the output port Pout of the second switching valve 102, the first
input port Pin1 of the first switching valve 100 and the output
port Pout of the first switching valve 100. In the present
embodiment, because the line pressure PL is input to the second
input port Pin2 of the second switching valve 102, the third oil
path 110 is an oil path that supplies the line pressure PL to the
hydraulic actuator 64.
[0085] As described above, according to the present embodiment, as
shown in FIG. 4, the hydraulic control circuit 50 (K0 hydraulic
control circuit 52) is able to set three types of supply pressure
(K0 clutch pressure Pk0) with the use of the single on-off solenoid
valve 104 by switching the first and second switching valves 100,
102 in accordance with whether the SLK0 pressure Pslk0 is high or
low (for example, high or low with respect to the switching valve
switching threshold). Thus, similar advantageous effects to those
of the above-described first embodiment are obtained.
[0086] According to the present embodiment, when the switching
hydraulic pressure Pon is output, the control hydraulic pressure
Pslk0 of the solenoid valve 66 is lower than the predetermined
switching valve switching threshold and the control hydraulic
pressure Pslk0 of the solenoid valve 66 is applied in the first
direction to switch the first switching valve 100, the first input
port Pin1 of the first switching valve 100 is communicated with the
output port Pout of the second switching valve 102, and the second
input port Pin2 of the second switching valve 102 is communicated
with the output port Pout of the second switching valve 102. Thus,
the third oil path 110 is set. As a result, it is possible to
alternatively switch among the three oil paths with the use of the
single on-off solenoid valve 104 common to the two switching
valves.
[0087] A fourth embodiment of the invention will be described. FIG.
12 is a view that shows another example embodiment of the K0
hydraulic control circuit 52, and is an embodiment different from
that of FIG. 11. Hereinafter, portions different from the
embodiment of FIG. 11 will be mainly described.
[0088] In FIG. 12, in the K0 hydraulic control circuit 52 according
to the present embodiment, the output port Pout of the second
switching valve 102 is connected to the second input port Pin2 of
the first switching valve 100. In the present embodiment, the SLK0
pressure Pslk0 is input to the first input port Pin1 of the first
switching valve 100. In the present embodiment, the first port of
the first switching valve is the output port Pout of the first
switching valve 100, the second port of the first switching valve
is the first input port Pin1 of the first switching valve 100, the
third port of the first switching valve is the second input port
Pin1 of the first switching valve 100, the first port of the second
switching valve is the output port Pout of the second switching
valve 102, and the second port or third port of the second
switching valve is one of the first input port Pin1 and second
input port Pin2 of the second switching valve 102. In the present
embodiment, the first solenoid valve is the on-off solenoid valve
104, and the second solenoid valve is the solenoid valve 66. In the
present embodiment, the SLK0 pressure Pslk0 is applied to the
second switching valve 102 so that thrust is generated for
switching the second switching valve 102 in the same direction
(first direction) as the direction (first direction) of thrust that
is generated by application of the switching hydraulic pressure
Pon.
[0089] In the thus configured K0 hydraulic control circuit 52, when
the SLK0 pressure Pslk0 does not satisfy the condition that the
SLK0 pressure Pslk0 is lower than the predetermined value while no
switching hydraulic pressure Pon is output, the first input port
Pin1 is communicated with the output port Pout in each of the first
and second switching valves 100, 102. Thus, the first oil path 106
is set. The first oil path 106 is an oil path that communicates the
first input port Pin1 of the first switching valve 100, to which
the SLK0 pressure Pslk0 is input, with the hydraulic actuator 64
via the output port Pout of the first switching valve 100, and is
an oil path that supplies the SLK0 pressure Pslk0 to the hydraulic
actuator 64 or releases the SLK0 pressure Pslk0 from the hydraulic
actuator 64. When the switching hydraulic pressure Pon is output
and the SLK0 pressure Pslk0 is higher than or equal to the
predetermined value, the second switching valve 102 according to
the present embodiment is switched to the on state where the second
input port Pin2 is communicated with the output port Pout.
Therefore, in the second switching valve 102 according to the
present embodiment, when no switching hydraulic pressure Pon is
output, the second switching valve 102 is switched to the off state
where the first input port Pin1 is communicated with the output
port Pout. Therefore, when no switching hydraulic pressure Pon is
output, the requirement that the condition that the SLK0 pressure
Pslk0 is lower than the predetermined value is not satisfied is not
required. That is, in the K0 hydraulic control circuit 52 according
to the present embodiment, when no switching hydraulic pressure Pon
is output, the first input port Pin1 is communicated with the
output port Pout in each of the first and second switching valves
100, 102 irrespective of the SLK0 pressure Pslk0. Thus, the first
oil path 106 is set.
[0090] In the K0 hydraulic control circuit 52 according to the
present embodiment, when the SLK0 pressure Pslk0 is higher than or
equal to the switching valve switching threshold while the
switching hydraulic pressure Pon is output, the second input port
Pin2 is communicated with the output port Pout in each of the first
and second switching valves 100, 102. Thus, the second oil path 108
is set. The second oil path 108 is an oil path that communicates
the second input port Pin2 of the second switching valve 102 with
the hydraulic actuator 64 sequentially via the output port Pout of
the second switching valve 102, the second input port Pin2 of the
first switching valve 100 and the output port Pout of the first
switching valve 100. In the present embodiment, because the
atmosphere exposure oil path EX is connected to the second input
port Pin2 of the second switching valve 102, the second oil path
108 is an oil path that connects the atmosphere exposure oil path
EX to the hydraulic actuator 64.
[0091] In the K0 hydraulic control circuit 52 according to the
present embodiment, the first input port Pin1 is communicated with
the output port Pout in the second switching valve 102 when the
SLK0 pressure Pslk0 is lower than the switching valve switching
threshold irrespective of whether the switching hydraulic pressure
Pon is output, and the second input port Pin2 is communicated with
the output port Pout in the first switching valve 100 depending on
the fact that the switching hydraulic pressure Pon is output. Thus,
the third oil path 110 is set. The third oil path 110 is an oil
path that communicates the first input port Pin1 of the second
switching valve 102 with the hydraulic actuator 64 sequentially via
the output port Pout of the second switching valve 102, the second
input port Pin2 of the first switching valve 100 and the output
port Pout of the first switching valve 100. In the present
embodiment, because the line pressure PL is input to the first
input port Pin1 of the second switching valve 102, the third oil
path 110 is an oil path that supplies the line pressure PL to the
hydraulic actuator 64.
[0092] As described above, according to the present embodiment, as
shown in FIG. 4, the hydraulic control circuit 50 (K0 hydraulic
control circuit 52) is able to set three types of supply pressure
(K0 clutch pressure Pk0) with the use of the single on-off solenoid
valve 104 by switching the first and second switching valves 100,
102 in accordance with whether the SLK0 pressure Pslk0 is high or
low (for, example, high or low with respect to the switching valve
switching threshold). Thus, similar advantageous effects to those
of the above-described third embodiment are obtained.
[0093] According to the present embodiment, when the predetermined
switching hydraulic pressure Pon is output, the control hydraulic
pressure Pslk0 of the solenoid valve 66 is lower than the
predetermined switching valve switching threshold and the control
hydraulic pressure Pslk0 of the solenoid valve 66 is applied in the
first direction to switch the second switching valve 102, the
second input port Pin2 of the first switching valve 100 is
communicated with the output port Pout of the second switching
valve 102, and the first input port Pin1 of the second switching
valve 102 is communicated with the output port Pout of the second
switching valve 102. Thus, the third oil path 110 is set. As a
result, it is possible to alternatively switch among the three oil
paths with the use of the single on-off solenoid valve 104 common
to the two switching valves.
[0094] A fifth embodiment of the invention will be described. FIG.
13 is a view that shows another example embodiment of the K0
hydraulic control circuit 52, and is an embodiment different from
that of FIG. 3. Hereinafter, portions different from the embodiment
of FIG. 3 will be mainly described.
[0095] In FIG. 13, in the K0 hydraulic control circuit 52 according
to the present embodiment, the output port Pout of the second
switching valve 102 is connected to the second input port Pin2 of
the first switching valve 100. In the present embodiment, the SLK0
pressure Pslk0 is input to the second input port Pin2 of the second
switching valve 102. In the present embodiment, the first port of
the first switching valve is the output port Pout of the first
switching valve 100, the second port of the first switching valve
is the second input port Pin2 of the first switching valve 100, the
third port of the first switching valve is the first input port
Pin1 of the first switching valve 100, the first port of the second
switching valve is the output port Pout of the second switching
valve 102, and the second port or third port of the second
switching valve is one of the first input port Pin1 and second
input port Pin2 of the second switching valve 102. In the present
embodiment, the first solenoid valve is the on-off solenoid valve
104, and the second solenoid valve is the solenoid valve 66. The
SLK0 pressure Pslk0 is applied to the other switching valve so that
thrust is generated for switching the other switching valve in the
same direction (first direction) as the direction (first direction)
of thrust that is generated by application of the switching
hydraulic pressure Pon. In the present embodiment, the SLK0
pressure Pslk0 is applied to the first switching valve 100 so that
thrust is generated for switching the first switching valve 100 in
the same direction (first direction) as the direction (first
direction) of thrust that is generated by application of the
switching hydraulic pressure Pon.
[0096] In the thus configured K0 hydraulic control circuit 52, when
the SLK0 pressure Pslk0 does not satisfy the predetermined
condition while no switching hydraulic pressure Pon is output, the
first input port Pint is communicated with the output port Pout in
each of the first and second switching valves 100, 102. Thus, the
first oil path 106 is set. The first oil path 106 is an oil path
that communicates the first input port Pin1 of the first switching
valve 100 with the hydraulic actuator 64 via the output port Pout
of the first switching valve 100. In the present embodiment,
because the line pressure PL is input to the first input port Pin1
of the first switching valve 100, the first oil path 106 is an oil
path that supplies the line pressure PL to the hydraulic actuator
64.
[0097] The predetermined condition is a condition that the SLK0
pressure Pslk0 is higher than or equal to a predetermined value.
When the switching hydraulic pressure Pon is output or when the
SLK0 pressure Pslk0 is higher than or equal to the predetermined
value, the first switching valve 100 according to the present
embodiment is switched to the on state where the second input port
Pin2 is communicated with the output port Pout. Therefore, to set
the first oil path 106, the requirement that the SLK0 pressure
Pslk0 does not satisfy the predetermined condition while no
switching hydraulic pressure Pon is output is required.
[0098] In the K0 hydraulic control circuit 52, when the SLK0
pressure Pslk0 does not satisfy the predetermined condition while
the switching hydraulic pressure Pon is output (for example, when
the SLK0 pressure Pslk0 is lower than the switching valve switching
threshold), the second input port Pin2 is communicated with the
output port Pout in each of the first and second switching valves
100, 102. Thus, the second oil path 108 is set. The second oil path
108 is an oil path that communicates the second input port Pin2 of
the second switching valve 102, to which the SLK0 pressure Pslk0 is
input, with the hydraulic actuator 64 sequentially via the output
port Pout of the second switching valve 102, the second input port
Pin2 of the first switching valve 100 and the output port Pout of
the first switching valve 100, and is an oil path that supplies the
SLK0 pressure Pslk0 to the hydraulic actuator 64 or releases the
SLK0 pressure Pslk0 from the hydraulic actuator 64. When the
witching hydraulic pressure Pon is output, the first switching
valve 100 according to the present embodiment is switched to the on
state where the second input port Pin2 is communicated with the
output port Pout. Therefore, when the switching hydraulic pressure
Pon is output, the requirement that the SLK0 pressure Pslk0 does
not satisfy the predetermined condition is not required. That is,
in the K0 hydraulic control circuit 52 according to the present
embodiment, when the switching hydraulic pressure Pon is output,
the second input port Pin2 is communicated with the output port
Pout in each of the first and second switching valves 100, 102
irrespective of the SLK0 pressure Pslk0. Thus, the second oil path
108 is set.
[0099] In the K0 hydraulic control circuit 52 according to the
present embodiment, the second input port Pin2 is communicated with
the output port Pout in the first switching valve 100 when the SLK0
pressure Pslk0 is higher than or equal to the switching valve
switching threshold irrespective of whether the switching hydraulic
pressure Pon is output, and the first input port Pin1 is
communicated with the output port Pout in the second switching
valve 102 depending on the fact that no switching hydraulic
pressure Pon is output. Thus, the third oil path 110 is set. The
third oil path 110 is an oil path that communicates the first input
port Pin1 of the second switching valve 102 with the hydraulic
actuator 64 sequentially via the output port Pout of the second
switching valve 102, the second input port Pin2 of the first
switching valve 100 and the output port Pout of the first switching
valve 100. In the present embodiment, because the atmosphere
exposure oil path EX is connected to the first input port Pin1 of
the second switching valve 102, the third oil path 110 is an oil
path that connects the atmosphere exposure oil path EX to the
hydraulic actuator 64.
[0100] As described above, according to the present embodiment, as
shown in FIG. 14, the hydraulic control circuit 50 (K0 hydraulic
control circuit 52) is able to set three types of supply pressure
(K0 clutch pressure Pk0) with the use of the single on-off solenoid
valve 104 by switching the first and second switching valves 100,
102 in accordance with whether the SLK0 pressure Pslk0 is high or
low (for example, high or low with respect to the switching valve
switching threshold). Thus, similar advantageous effects to those
of the above-described first, embodiment, are obtained. In FIG. 14,
the correlation between whether the switching hydraulic pressure
Pon is output and the oil path to be set is opposite to that of
FIG. 4.
[0101] According to the present embodiment, when no predetermined
switching hydraulic pressure Pon is output, the control hydraulic
pressure Pslk0 of the solenoid valve 66 is higher than or equal to
the predetermined switching valve switching threshold and the
control hydraulic pressure Pslk0 of the solenoid valve 66 is
applied in the first direction to switch the first switching valve
100, the second input port Pin2 of the first switching, valve 100
is communicated with the output port Pout of the second switching
valve 102, and the first input port Pin1 of the second switching
valve 102 is communicated with the output port Pout of the second
switching valve 102. Thus, the third oil path 110 is set. As a
result, it is possible to alternatively switch among the three oil
paths with the use of the single on-off solenoid valve 104 common
to the two switching valves.
[0102] A sixth embodiment of the invention will be described. FIG.
15 is a view that shows another example embodiment of the K0
hydraulic control circuit 52, and is an embodiment different from
that of FIG. 13. Hereinafter, portions different from the
embodiment of FIG. 13 will be mainly described.
[0103] In FIG. 15, in the K0 hydraulic control circuit 52 according
to the present embodiment, the output port Pout of the second
switching valve 102 is connected to the first input port Pin1 of
the first switching valve 100. In the present embodiment, the SLK0
pressure Pslk0 is input to the second input port Pin2 of the first
switching valve 100. In the present embodiment, the first port of
the first switching valve is the output port Pout of the first
switching valve 100, the second port of the first switching valve
is the second input port Pin2 of the first switching valve 100, the
third port of the first switching valve is the first input port
Pin1 of the first switching valve 100, the first port of the second
switching valve is the output port Pout of the second switching
valve 102, and the second port or third port of the second
switching valve is one of the first input port Pin1 and second
input port Pin2 of the second switching valve 102. In the present
embodiment, the first solenoid valve is the on-off solenoid valve
104, and the second solenoid valve is the solenoid valve 66. In the
present embodiment, the SLK0 pressure Pslk0 is applied to the
second switching valve 102 so that thrust is generated for
switching the second switching valve 102 in the same direction
(first direction) as the direction (first direction) of thrust that
is generated by application of the switching hydraulic pressure
Pon.
[0104] In the thus configured K0 hydraulic control circuit 52
according to the present embodiment, when the SLK0 pressure Pslk0
does not satisfy the condition that the SLK0 pressure Pslk0 is
higher than or equal to the predetermined value while no switching
hydraulic pressure Pon is output, the first input port Pin1 is
communicated with the output port Pout in each of the first and
second switching valves 100, 102. Thus, the first oil path 106 is
set. The first oil path 106 is an oil path that communicates the
first input port Pin1 of the second switching valve 102 with the
hydraulic actuator 64 sequentially via the output port Pout of the
second switching valve 102, the first input port Pin1 of the first
switching valve 100 and the output port Pout of the first switching
valve 100. In the present embodiment, because the line pressure PL
is input to the first input port Pin1 of the second switching valve
102, the first oil path 106 is an oil path that supplies the line
pressure PL to the hydraulic actuator 64. When the switching
hydraulic pressure Pon is output or when the SLK0 pressure Pslk0 is
higher than or equal to the predetermined value, the second
switching valve 102 according to the present embodiment is switched
to the on state where the second input port Pin2 is communicated
with the output port Pout. Therefore, to set the first oil path
106, the requirement that the condition that the SLK0 pressure
Pslk0 is higher than or equal to the predetermined value is not
satisfied while no switching hydraulic pressure Pon is output is
required.
[0105] In the K0 hydraulic control circuit 52 according to the
present embodiment, when the SLK0 pressure Pslk0 is lower than the
switching valve switching threshold while the switching hydraulic
pressure Pon is output, the second input port Pin2 is communicated
with the output port Pout in each of the first and second switching
valves 100, 102. Thus, the second oil path 108 is set. The second
oil path 108 is an oil path that communicates the second input port
Pin2 of the first switching valve 100, to which the SLK0 pressure
Pslk0 is input, with the hydraulic actuator 64 via the output port
Pout of the first switching valve 100, and is an oil path that,
supplies the SLK0 pressure Pslk0 to the hydraulic actuator 64 or
releases the SLK0 pressure Pslk0 from the hydraulic actuator 64.
When the switching hydraulic pressure Pon is output, the second
switching valve 102 according to the present embodiment is switched
to the on state where the second input port Pin2 is communicated
with the output port Pout. Therefore, when the switching hydraulic
pressure Pon is output, the requirement that the condition that the
SLK0 pressure Pslk0 is higher than or equal to the predetermined
value is not satisfied is not required. That is in the K0 hydraulic
control circuit 52 according to the present embodiment, when the
switching hydraulic pressure Pon is output, the second input port
Pin2 is communicated with the output port Pout in each of the first
and second switching valves 100, 102 irrespective of the SLK0
pressure Pslk0. Thus, the second oil path 108 is set.
[0106] In the K0 hydraulic control circuit 52 according to the
present embodiment, the second input port Pin2 is communicated with
the output port Pout in the second switching valve 102 when the
SLK0 pressure Pslk0 is higher than or equal to the switching valve
switching threshold irrespective of whether the switching hydraulic
pressure Pon is output, and the first input port Pin1 is
communicated with the output port Pout in the first switching valve
100 depending on the fact that no switching hydraulic pressure Pon
is output. Thus, the third oil path 110 is set. The third oil path
110 is an oil path that communicates the second input port Pin2 of
the second switching valve 102 with the hydraulic actuator 64
sequentially via the output port Pout of the second switching valve
102, the first input port Pin1 of the first switching valve 100 and
the output port Pout of the first switching valve 100. In the
present embodiment, because the atmosphere exposure oil path EX is
connected to the second input port Pin2 of the second switching
valve 102, the third oil path 110 is an oil path that connects the
atmosphere exposure oil path EX to the hydraulic actuator 64.
[0107] As described above, according to the present embodiment, as
shown in FIG. 14, the hydraulic control circuit 50 (K0 hydraulic
control circuit 52) is able to set three types of supply pressure
(K0 clutch pressure Pk0) with the use of the single on-off solenoid
valve 104 by switching the first and second switching valves 100,
102 in accordance with whether the SLK0 pressure Pslk0 is high or
low (for example, high or low with respect to the switching valve
switching threshold). Thus, similar advantageous effects to those
of the above-described fifth embodiment are obtained.
[0108] According to the present embodiment, when no predetermined
switching hydraulic pressure Pon is output, the control hydraulic
pressure Pslk0 of the solenoid valve 66 is higher than or equal to
the predetermined switching valve switching threshold and the
control hydraulic pressure Pslk0 of the solenoid valve 66 is
applied in the first direction to switch the second switching valve
102, the first input port Pin1 of the first switching valve 100 is
communicated with the output port Pout of the second switching
valve 102, and the second input port Pin2 of the second switching
valve 102 is communicated with the output port Pout of the second
switching valve 102. Thus, the third oil path 110 is set. As a
result, it is possible to alternatively switch among the three oil
paths with the use of the single on-off solenoid valve 104 common
to the two switching valves.
[0109] A seventh embodiment of the invention will be described.
FIG. 16 is a view that shows another example embodiment of the K0
hydraulic control circuit 52, and is an embodiment different from
that of FIG. 3. Hereinafter, portions different from the embodiment
of FIG. 3 will be mainly described.
[0110] In FIG. 16, the K0 hydraulic control circuit 52 according to
the present embodiment differs from that of the embodiment of FIG.
3 in that the SLK0 pressure Pslk0 is input to the second input port
Pin2 of the second switching valve 102, and the atmosphere exposure
oil path EX is connected to the first input port Pin1 of the second
switching valve 102. The first input port Pin1 of the second
switching valve 102 is one of the first and second input ports
Pin1, Pin2 of the second switching valve 102, to which the SLK0
pressure Pslk0 is not input. That is, the K0 hydraulic control
circuit 52 according to the present embodiment differs from that of
the embodiment of FIG. 3 in that input of the SLK0 pressure Pslk0
and connection of the atmosphere exposure oil path EX to the first
and second input ports Pin1, Pin2 of the second switching valve 102
are interchanged. Thus, as shown in FIG. 17, the correlation
between whether the switching hydraulic pressure Pon is output and
the oil path to be set is different from that of FIG. 4. That is,
in FIG. 17, the SLK0 pressure Pslk0 and the atmosphere exposure oil
path EX in FIG. 4 are interchanged. In the K0 hydraulic control
circuit 52 according to the present embodiment, when the SLK0
pressure Pslk0 is reduced below the switching valve switching
threshold during normal operation of the solenoid valve 66, there
is a possibility that the atmosphere exposure oil path EX is
switched into the oil path that supplies the line pressure PL.
Therefore, during normal operation of the solenoid valve 66, a
minimum hydraulic pressure to such an extent that the atmosphere
exposure oil path EX is not switched into the oil path that
supplies the line pressure PL (for example, a hydraulic pressure
higher than or equal to the switching valve switching threshold or
a value obtained by adding a margin to the switching valve
switching threshold) is output. For example, the characteristic of
the return spring, or the like, is set so that the clutch K0 is
released at the minimum hydraulic pressure. In the present
embodiment, the first port of the first switching valve is the
output port Pout of the first switching valve 100, the second port
of the first switching valve is the first input port Pin1 of the
first switching valve 100, the third port of the first switching
valve is the second input port Pin2 of the first switching valve
100, the first port of the second switching valve is the output
port Pout of the second switching valve 102, and the second port or
third port of the second switching valve is one of the first input
port Pin1 and second input port Pin2 of the second switching valve
102. In the present embodiment, the first solenoid valve is the
on-off solenoid valve 104, and the second solenoid valve is the
solenoid valve 66.
[0111] As described above, according to the present embodiment, as
shown in FIG. 17, the hydraulic control circuit 50 (K0 hydraulic
control circuit 52) is able to set three types of supply pressure
(K0 clutch pressure Pk0) with the use of the single on-off solenoid
valve 104 by switching the first and second switching valves 100,
102 in accordance with whether the SLK0 pressure Pslk0 is high or
low (for example, high or low with respect to the switching valve
switching threshold). Thus, similar advantageous effects to those
of the above-described first embodiment are obtained.
[0112] According to the present embodiment, when the predetermined
switching hydraulic pressure Pon is output, the control hydraulic
pressure Pslk0 of the solenoid valve 66 is higher than or equal to
the predetermined switching valve switching threshold and the
control hydraulic pressure Pslk0 of the solenoid valve 66 is
applied in the second direction to switch the first switching valve
100, the first input port Pin1 of the first switching valve 100 is
communicated with the output port Pout of the second switching
valve 102 and the second input port Pin2 of the second switching
valve 102 is communicated with the output port Pout of the second
switching valve 102. Thus, the third oil path 110 is set. As a
result, it is possible to alternatively switch among the three oil
paths with the use of the single on-off solenoid valve 104 common
to the two switching valves.
[0113] The embodiments of the invention are described in detail
with reference to the accompanying drawings; however, the invention
is also applicable to other embodiments.
[0114] For example, in the above-described embodiments, the drive
line 12 is provided in the vehicle 10 that is the hybrid vehicle;
however, the invention is not limited to this configuration. For
example, a drive line may constitute a power transmission path from
a single driving force source to a drive wheel. The hydraulic
control circuit 50 (K0 hydraulic control circuit 52) that
alternatively switches among the three oil paths to the clutch K0
that connects the engine 14 to the power transmission path or
disconnects the engine 14 from the power transmission path is
illustrated; however, the invention is not limited to this
configuration. For example, a hydraulic control circuit may
alternatively switch among three oil paths to an engagement device
that connects or interrupts a-power transmission path. For such an
engagement device, at a low temperature of hydraulic oil where
drain of hydraulic oil delays, it is useful to quickly drain
hydraulic oil through the atmosphere exposure oil path EX. The
automatic transmission 20, the torque converter 18, or the like,
does not necessarily need to be provided in the drive line 12. In
short, as long as a drive line includes a hydraulic actuator that
is alternatively communicated with three oil paths, the invention
is applicable.
[0115] In the embodiment of FIG. 13 according to the
above-described fifth embodiment, as well as the embodiment of FIG.
16 according to the above-described seventh embodiment, an
embodiment in which input of the SLK0 pressure Pslk0 and connection
of the atmosphere exposure oil path EX to the first and second
input ports Pin1, Pin2 of the second switching valve 102 are
interchanged is applicable. The solenoid valve 66 or the on-off
solenoid valve 104 may be a normally-open or N/O valve. In this
way, each of the embodiments described in the first to seventh
embodiments may be modified as needed within the scope of the
invention.
[0116] In the above-described embodiments, the SLK0 pressure Pslk0
is applied to the other switching valve so that thrust for
switching the other switching valve is generated. Instead, the SLK0
pressure Pslk0 may be applied to the one of the switching valves so
that the thrust is generated or the SLK0 pressure Pslk0 may be
applied to both the switching valves so that the thrust is
generated.
[0117] In the above-described embodiments, the on-off solenoid
valve 104 is used. Instead, a valve that is able to switch a
switching valve is applicable, and another valve, such as a linear
solenoid valve, may be used.
[0118] In the above-described embodiments, determination as to
off-fail of the solenoid valve 66 and determination as to a
decrease in the SLK0 pressure Pslk0 may be carried out by providing
a hydraulic pressure sensor and carrying out a determination on the
basis of a detected value of the hydraulic pressure sensor, or the
like. In this way, various methods are applicable.
[0119] The above-described embodiments are only illustrative, and
the invention may be implemented in modes including various
modifications and improvements on the basis of the knowledge of
persons skilled in the art.
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